1. Field
The present disclosure relates to methods of forming a polymer dispersed liquid crystal (PDLC) layer, including methods of forming a PDLC layer including a dichroic dye.
2. Description of the Related Art
Conventional polymer dispersed liquid crystal (PDLC) display devices apply an electric field to a PDLC layer in which liquid crystals are uniformly dispersed in a polymer to vary a refractive index of the PDLC layer so that light may be scattered by the PDLC layer or so that light may be transmitted through the PDLC layer. The PDLC display devices may scatter or transmit light by only applying an electric field to the PDLC layer, without using an orientation layer and a polarization plate. A dichroic dye may be mixed in the PDLC layer to realize a display device having improved contrast. The dichroic dye may be distributed according to the movement of the liquid crystals. Thus, when the dichroic dye is mixed in the PDLC layer, the dichroic dye is affected by the movement of the liquid crystals and may be arranged or randomly distributed according to arrangement of the liquid crystals. As a result, optical characteristics of the display device may be affected.
A PDLC layer including a dichroic dye may be conventionally formed by implanting a solution, in which liquid crystals, a photopolymerizable material, and the dichroic dye are mixed, between two substrates and curing the mixed solution using ultraviolet (UV) rays. Because of the curing, the photopolymerizable material is changed into a polymer. The photopolymerizable material may be formed of a monomer or an oligomer. The curing process is performed such that liquid crystals are uniformly dispersed in the polymer, and the dichroic dye is uniformly contained in the polymer and the liquid crystals. However, in a display device including the PDLC layer formed using a conventional method, the dichroic dye contained in the polymer may adversely affect optical characteristics of the display device. Stated more clearly, the arrangement of the dichroic dye contained in the polymer may be fixed as a result of the curing process using UV rays. The fixed dichroic dye is not optically anisotropic and, thus, adversely affects visibility of the display device. Furthermore, the dichroic dye contained in the polymer absorbs UV rays continuously during the curing process using UV rays and, thus, UV ray curing characteristics of the display device may be lowered.